INSIDE THE CLASS OF REGEX LANGUAGES

MARKUS L. SCHMID
2013 International Journal of Foundations of Computer Science  
We study different possibilities of combining the concept of homomorphic replacement with regular expressions in order to investigate the class of languages given by extended regular expressions with backreferences (REGEX). It is shown in which regard existing and natural ways to do this fail to reach the expressive power of REGEX. Furthermore, the complexity of the membership problem for REGEX with a bounded number of backreferences is considered.
doi:10.1142/s0129054113400340 fatcat:6vdnv7ekijbx5g4242nwsmrmzy